2017 Toyota Sienna: hesitation when accelerating

Filed Jul 11, 2026 · Transmission · CA

I, as well as other owners of 2017–2018 Toyota Highlanders and 2017–2018 Siennas are experiencing serious transmission issues—including high-pitched whining, erratic shifting, clunks, hesitation, and premature failure. My 2017 Toyota Sienna has the UA80 8-speed automatic transmission at issue and started whining upon acceleration in March/April 2026 timeframe. It has always had the clunking and hesitation problem. According to Gears Magazine, the issue stems from a flawed assembly process involving the counter drive gear support. A locking tab meant to secure a vital retaining nut was not bent properly during factory assembly. This leads to gear movement, internal wear, whining, and eventually failure. Unknown to me, in 2019, Toyota had acknowledged the problem in Technical Service Bulletins T-SB-0160-18, T-SB-0008-21, which only go to dealers, and implemented a limited Customer Support Program (CSP ZJC)—but only offered coverage to a narrow group of VINs, not to all VINs for model years that have these transmissions. My car is experiencing these same symptoms. My Toyota Dealer confirmed this problem and recommended a transmission replacement for $11,000 including labor. They said my VIN was not included in the Customer Support Program. Driving with a failing transmission is highly dangerous. A bad transmission can cause sudden power loss causing the car to halt to a sudden stop, unintended acceleration, or my car might get stuck in neutral while driving. I could lose control or be unable to get to the shoulder on the highway, cause a rear-end collision, or get stuck in busy traffic. DESIRED OUTCOME REQUEST: My VIN should be covered under the Customer Support Program in the category of cars that are “less than 10 years old regardless of mileage” or a full recall of all VINs of these model years with these transmissions should be executed. Thank you.

Filed May 14, 2026 · Transmission · NC

I am writing to report a safety defect regarding the 8-speed automatic transmission in my 2017 Toyota Sienna. The vehicle exhibits severe hesitation during acceleration, harsh shifting, and a high-pitched whining noise, specifically consistent with the 'whine of death' described in Toyota's Customer Support Program ZJC and related Technical Service Bulletin T-SB-0160-18.Despite these identical symptoms, my vehicle’s VIN is not included in the coverage list. This hesitation during acceleration creates a serious safety issue, as the car fails to accelerate unexpectedly when attempting to merge or cross traffic. My vehicle is equipped with the UA80F/E transmission, which is documented to have a faulty assembly (improperly bent washer tab). I request that the federal safety agency investigate the exclusion of my VIN from this program, as the defect poses a significant risk to passenger safety and the safety of others on the road.

Filed Oct 14, 2025 · Transmission · 40,000 miles · CA

The contact owns a 2017 Toyota Sienna. The contact stated that while driving at an undisclosed speed and attempting to accelerate, the vehicle briefly hesitated before shifting hard into gear. The contact stated that after the failure, there was an abnormal whining sound coming from underneath the vehicle. No warning lights were illuminated. The vehicle was taken to an independent mechanic, who was unable to provide a specific diagnosis for the cause of the failure; however, the contact was informed that there were known issues with the transmission of similar vehicles. The vehicle was not repaired. After investigating the failure, the contact related the failure to the Customer Support Program Bulletin: ZJC. The manufacturer was notified of the failure, a case was opened, and the contact was referred to the federal safety agency Hotline for assistance. The failure mileage was 40,000.

Filed Jun 1, 2020 · Fuel system · 17,500 miles · FL

Vehicle exhibits periods of rough acceleration, chugging, and hesitation. After 3 trips to different toyota dealers they refuse to address problem. A massive recall of toyota fuel pumps is underway on several vehicles including 2017 sienna's but dealerships claim my 2017 sienna is not on list. I've lived with this for 3 years and my vehicle is till under warranty with less than 18,000 miles on it. Happens whenever vehicle is used. Dealerships won't test it as they have to drop gas tank.

Filed Mar 7, 2018 · Acceleration · 5,500 miles · IL

Tl* the contact owns a 2017 toyota sienna. While driving approximately 25 MPH, the vehicle hesitated and accelerated forward. The contact stated that the failure occurred at least once a day for the past three months. The vehicle was not taken to a dealer or an independent mechanic for diagnostic testing. The manufacturer was not notified of the failure. The vehicle was not repaired. The approximate failure mileage was 5,500.